1. Field of the Invention
The present invention relates generally to the manufacture of continuous seam-welded metal tubes or pipes, and more particularly to a novel apparatus for scarfing or removing from the outer surface of the tube or pipe the raised bead or flash resulting from welding of the seam.
2. Description of the Prior Art
In accordance with a well-known process for producing seam-welded pipes and tubes, a continuous strip or skelp is advanced through forming apparatus and progressively deformed into a tubular form having an open, longitudinally extending seam. The tubular form then advances through a welding station wherein the adjacent longitudinal edges are urged together and joined by a suitable welding process. The particular welding process employed will generally be indicated by the material from which the tube or pipe is formed, for example, low carbon steel, stainless steel, aluminum, etc., and may include any of the well-known welding techniques conventionally employed with the different materials. In a preferred process the tube or pipe is heated by electrical induction so that the edges achieve fusion temperature, and the heated edges are forced together to produce a continuous monolithic weld of the seam. As a result of the pressure applied in forcing the heated edges together to achieve fusion, the material bulges both outwardly and inwardly to create a raised bead or flash extending along the longitudinal weld seam. In seams formed by other types of welding such as arc welding and gas welding, a similar raised bead or seam is generally formed along at least the outer surface of the tube.
In order to produce a commercially acceptable product, it is generally necessary to remove the protruding portion of the weld bead or flash flush with the surface of the tube or pipe. Various devices have been proposed heretofore for removing both the internal bead and the external bead. Removing the internal bead is, of course, more difficult than removing the external bead due to the restricted access to the removal area. A scarfing tool particularly suited for removing the internal bead is disclosed in U.S. Pat. No. 4,600,180, issued Jul. 15, 1986. Removal of the external bead can be accomplished by any of a number of conventional processes including grinding and scarfing. One type of external surface scarfing apparatus is described in U.S. Pat. No. 3,249,349, issued May 3, 1966.
While a number of devices have been employed heretofore in removing or scarfing the external weld bead from seam welded pipe or tubing, those prior art devices have not proved entirely satisfactory for the present day high speed production of continuously formed seam welded pipe or tubing. It is highly desirable to remove the weld bead immediately following the welding procedure, while the bead and pipe retain sufficient heat from the welding process and remain at the proper temperature for scarfing. The apparatus should also be able to evenly and accurately remove the bead or flash for extended periods of time without requiring interruption of operation of the line for the continuous production of the seam welded tubes or pipes. The devices heretofore available have lacked the capability to quickly and readily adapt to changes in operation while permitting continuous operation of the tube forming apparatus.